Which species and varieties are good for frost seeding?
Clovers are the most common species for frost seeding, and most frost seeding research to establish seeding rate and timing recommendations was performed using clover species. Birdsfoot trefoil is another legume option, and annual ryegrass, orchardgrass, and some other grasses can also be established this way. But, plant establishment from frost seeding is usually higher for clovers than other species.
Can I frost seed multiple species at the same time?
Yes, but be careful to adjust seeding rates proportionally based on your desired species mix.
Source : osu.edu